Traffic survey Haarlem-Noord

The Vondelweg in Haarlem Noord is subject of a long lasting debate revolving around the question whether this road needs to be upgraded to a road with two lanes for each direction in order to enhance the accessibility of Haarlem.

The platform that represents various neighbourhood councils and local interest groups plays an important role in this discussion. In order to take a well-grounded position in the debate the platform wants to have further insights in the current traffic situation, the influence of traffic on liveability or the area, and possible solutions for experienced problems. The platform asked the Science Shop of Wageningen UR to study these issues. This report presents the findings of the Science Shop project.

The following questions are addressed in this research:

Which data underlies the current debate about the function and design of the Vondelweg and what is the quality of this data?

What is the role of the Vondelweg and the surrounding network of roads in Haarlem North?

Are there infrastructural bottlenecks and what is the nature of these bottlenecks? Which options are there to mitigate such bottlenecks?

Are there, with an eye on the future situation, reasons to extent the capacity of the infrastructure in Haarlem Noord and if necessary how could this be done?

What are the effects of the traffic flows on the liveability of the area and are measures necessary to mitigate negative impacts, now or in the future?

The quality of the debate about the road network partly depends on the available data about the volume of current traffic flows and data on the capacity of the infrastructural network. This research thus started with an inventory of available date by analysing various policy document and research reports. This analysis showed the lack of usable data and the need for additional research towards traffic flows, their variation over time, the direction of traffic, and the capacity of roads and intersections.

Information about traffic volumes was collected by using data from detection loops of traffic lights that register the number of cars. Additional information about the direction and destination of traffic flows was collected using camera’s. The capacity of traffic lights at different intersections was determined, as this capacity sets the capacity of the road network. The ratio between the amount of traffic per hour (I) and capacity (C) was determined for each intersection. This I/C ratio is an important indicator for the extent to which the road network can facilitate current traffic flows. This analysis paid particular attention to the rush hours in the morning and the evening, as these are the moments that traffic volumes are at their maximum.

The analysis shows that there are no structural congestions or delays in the mornings, although some intersections show a small amount of traffic congestion. The rush hours in the evening are a little bit busier and congestion might occur at those times. The analysis also showed that even if traffic volumes will increase in the future, only few structural problems are likely to occur. The capacity of the roads and the intersections is sufficient to facilitate current and future traffic flows.

Camera observations showed that only a very small part of the traffic consists of through-traffic (2-4%) that drives all the way from the Camera Obscuraweg to the Delftplein. A larger part (23%) of the traffic between Delftplein and the Spaarndamsebrug has a destination at the Waarderpolder or the centre of Haarlem. The rest of the traffic has a destination in Haarlem Noord. This suggests that the Vondelweg has a supra-local function, but not a regional function.

The research also paid attention to the effects of traffic on the liveability of the area. In the study, three indicators are used to draw conclusions regarding liveability: traffic safety, air pollution and congestion. To quantify the aspect of traffic safety, we analysed the number and nature of traffic accidents in 2007-2012. The number of accidents in this period has declining, as has the degree and amount of injuries caused by these accidents. To quantify air pollution, we used the same model the national government uses: CARii. From the results it can be concluded that the concentrations airborne particulate matter (PM10) and carbon dioxide are found to be below legal standards. The concentration of and soot particles was also modelled, but no legal norm exists (yet) for this parameter. It is estimated that people who are exposed to 0,5 µg soot/m³ live three months shorter. The congestion, finally, is analysed using the data of the camera survey. The traffic between the Delftplein and Spaarndamsebrug has a maximum delay of 70 seconds during rush hour.

Conclusion

The question whether the Vondelweg should be upgraded to a road with two lanes in each direction remains topical, partly due to the fact that the province of Noord-Holland has required such upgrade as a precondition for a financial contribution to the extension of the near-by Waarderweg. This research shows that the wish for such an upgrade is partly based upon outdated forecasts about future traffic flows and can hardly be sustained with data about current traffic flows. This research shows also that the capacity of the roads and intersections is sufficient to facilitate current flows and even allows the traffic volumes to increase without creating structural congestions and delays. Only during rush-hours some temporary bottlenecks will occur. This conclusion confirms similar conclusions put forward by prior studies from Witteveen+Bos and Goudappel-Coffeng. In general the (economic) accessibility of the area is good, despite higher traffic volumes during the rush hours. A number of measures can be taken, though, to optimize the capacity of the road network.

This research therefore concludes that there is no need to change the function of the Vondelweg and it is not necessary to upgrade the road to a road with two lanes in each direction.

The report also puts forward a number of recommendations. First of all it is important to feed the debate about the road network with reliable and up-to-date data about traffic flows. Such data can easily be collected by using the detection loops from the traffic lights. In addition, it is recommended to mitigate traffic safety and the environmental impacts of current traffic flows.